Last updated: 2026-05-18

Why MET-Based Calorie Estimates Work

Every time you move, your muscles demand oxygen. Exercise physiologists have spent decades quantifying how much oxygen different activities actually consume, and in 1993 Barbara Ainsworth and colleagues published the first Compendium of Physical Activities — a lookup table of MET values for hundreds of activities. The 2024 update (used here) covers 1,114 activities, with 82% of values based on measured data.

MET stands for Metabolic Equivalent of Task. At MET 1.0 you are sitting quietly, consuming about 3.5 ml of O₂ per kilogram of body weight per minute — your resting metabolic rate. Every whole MET above 1 means your body is demanding proportionally more oxygen. Walking briskly clocks in at MET 3.5, meaning your metabolic rate is 3.5 times the resting rate.

The calorie formula follows directly:

$\text{kcal} = \text{MET} \times m_\text{kg} \times t_\text{h}$

where $m_\text{kg}$ is body mass in kilograms and $t_\text{h}$ is duration in hours. This works because 1 MET = 1 kcal/kg/h by definition.

How the Calculator Works

Choosing an Activity

The preset list covers ten of the most commonly tracked activities across cardio, strength, and flexibility categories. Each preset locks in the published MET from the 2024 Compendium. When you select an activity, the "MET Applied" output updates to show exactly which value drives the calculation.

If your sport is not listed — rowing, paddleboarding, racquetball, disc golf — select Custom MET and enter the value yourself. Look up your activity at pacompendium.com (Ainsworth et al., Journal of Sport and Health Science, 2024).

Body Weight and Duration

Calorie expenditure scales linearly with both weight and time. A 90 kg runner burns exactly 50% more calories than a 60 kg runner at the same pace for the same duration. Duration is entered in any of three units — seconds, minutes, or hours — and the calculator converts internally to hours before computing.

Output: Gross vs. Net Calories

The calculator returns gross calorie expenditure — total energy consumed including the resting metabolic contribution. This is the number most fitness trackers report. Net calorie expenditure, which subtracts the calories you would have burned just sitting still, is typically 10–20% lower. Both approaches are valid; just be consistent when comparing sessions or logging in a food diary.

Accuracy and Limitations

MET-based estimates are a population average, not a personal measurement. The key sources of individual variation:

• Fitness level. A trained runner uses oxygen more efficiently than a beginner at the same speed. Their MET for a 10 km/h run is genuinely lower.
• Terrain. Running hills, soft sand, or snow dramatically increases energy cost above the flat-ground MET value.
• Technique. Skilled swimmers glide farther per stroke. Beginners of the same weight burn more calories at the same pace.
• Ambient conditions. Cold weather forces thermogenic heat production; heat and humidity require more cooling effort.
• Intermittent vs. sustained effort. Published MET values assume steady-state effort. Interval training cycles through work and rest, making the average MET hard to pin down.

The typical error band for individual calorie estimates from MET is ±10–20%. For most planning purposes — estimating total weekly calorie expenditure, comparing two session types, informing a calorie surplus or deficit — this precision is adequate. For clinical nutrition, indirect calorimetry provides individual-level accuracy.

Practical Scenarios

Finding Your Cardio Crossover Point

Running and cycling are often compared for calorie burn. At the same duration, running at 10 km/h (MET ≈ 10) burns roughly 25% more calories per hour than cycling at a moderate pace (MET 8). However, cycling lets you sustain effort longer before fatigue, so total session calories can be similar. Plug your actual speed and duration into both options to compare.

Weight-Based Planning

Because calorie burn is strictly proportional to body weight, you can use this calculator to estimate how your expenditure will change as your weight changes during a training cycle. A 10% body weight reduction reduces calorie burn per session by exactly 10% at the same MET and duration.

Setting a Custom MET for Uncommon Sports

Brazilian jiu-jitsu competitive sparring (MET ≈ 10), recreational paddle tennis (MET ≈ 4), and recreational volleyball (MET ≈ 4) illustrate the wide spread of activity intensities. When the Compendium lists multiple METs for the same sport (e.g., "tennis, recreational" vs. "tennis, competitive"), use your honest assessment of the intensity level.

Caveats

• This is gross, not net, expenditure. Net exercise calories are lower and more relevant for dietary planning, but this calculator reports what fitness trackers report: total energy consumed.
• The formula assumes steady-state effort. If you do intervals, average your perceived effort level or use a heart-rate-based monitor for a better estimate.
• MET values have standard deviations. Even the 2024 Compendium acknowledges that individual variation in oxygen cost for a given activity can be substantial. Use these estimates for trends, not for exact macronutrient accounting.